decision-log

decision-log is a skill for Claude Code from lglucas/ai-dev-operating-system. It costs 90 tokens per session (168 once invoked), scanned A, original, MIT.

A skill for recording why an important decision was made, including the alternatives that were rejected. It can save the record in a session log or an ADR, a document that preserves an architecture decision.

In plain words
What is it for?
Document decisions about architecture, product scope, pricing, compliance, security, releases, or disagreements resolved through multi-agent review.
Why use it?
It prevents important reasoning from being lost after a discussion or disagreement. Future contributors can see the context, trade-offs, risks, and follow-up work.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Part of the ai-dev-operating-system plugin — 28 skills, 11 commands, 12 agents, 1 hook shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/lglucas/ai-dev-operating-system/decision-log
Any agent
npx skills add lglucas/ai-dev-operating-system --skill decision-log
Clone the repo
git clone --depth 1 https://github.com/lglucas/ai-dev-operating-system

Made for: Claude Code.

Or install ai-dev-operating-system, the plugin that ships this one along with the rest of its 28 skills, 11 commands, 12 agents, 1 hook.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for decision-log

README.md
[![agentmods](https://agentmods.dev/badge/skills/lglucas/ai-dev-operating-system/decision-log.svg)](https://agentmods.dev/skills/lglucas/ai-dev-operating-system/decision-log)
Your own site
<a href="https://agentmods.dev/skills/lglucas/ai-dev-operating-system/decision-log"><img src="https://agentmods.dev/badge/skills/lglucas/ai-dev-operating-system/decision-log.svg" alt="Measured on agentmods" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 168 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00090 $0.00168
Opus 5 $0.00045 $0.00084
Sonnet 5 $0.00018 $0.00034
Haiku 4.5 $0.00009 $0.00017

Measured 6d ago against content hash bc5ee2059886, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

decision-log scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/decision-log/SKILL.md · 18 lines

What it actually says

Decision Log

Use this when a decision affects architecture, product scope, pricing, compliance, security, or release strategy.

Steps

  1. State the decision.
  2. Record context.
  3. List alternatives considered.
  4. Explain why the chosen path wins.
  5. Note risks and follow-ups.
  6. Link related sprint/changelog/issue.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 18 lines · 90 tokens per session scan A bc5ee2059886

Subscribe to this mod's changes

decision-log is a skill published in the GitHub repository lglucas/ai-dev-operating-system (11 stars, last pushed 27d ago), licensed MIT. It adds 90 tokens to every session and 168 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.